Most modern .40/.45 pistols employ a system of operation where the barrel and slide are locked together to contain the pressure of discharging a cartridge. In these systems it is necessary for the barrel to move within the frame, either in a straight line or with a tilting motion. The A.S.A.P. System used in the EVO series takes the weight of the silencer off the barrel, allowing it to move and the host pistol to function in a normal semi-automatic fashion. On weapons with non-moving barrels the A.S.A.P. System is not necessary and may actually damage the firearm. The fixed barrel weapon spacer replaces the driving spring in the A.S.A.P. System and allows users to safely use their EVO series silencer on host firearms with non-moving barrels.